1. Field of the Invention
The present invention relates generally to the field of gyrasphere crushers. More particularly, the present invention concerns adjusting the crushing gap of a gyrasphere crusher that includes a conical convex crushing head, a conical concave crushing bowl which is vertically adjustable relative to the head, and an adjustment assembly which permits vertical adjustment of the conical concave crushing bowl relative to the conical convex crushing head. Specifically, a preferred embodiment of the present invention is directed to an adjustment assembly that includes a bushing and a swivel bracket. The present invention thus relates to a gyrasphere crusher adjustment assembly of the type that can be termed swivelable.
2. Discussion of the Related Art
Heretofore, gyrasphere crushers have typically included a main frame that is stationary, a generally conical convex crushing head rotatably mounted on the main frame for gyration by an eccentric shaft, and a generally conical concave crushing bowl mounted on the main frame. The conical convex crushing head includes an upwardly facing convex crushing surface. Similarly, the conical concave crushing bowl includes a downwardly facing concave crushing surface. The conical concave crushing bowl is mounted on the main frame above the conical convex crushing head so as to define an annular crushing chamber. The minimum distance between upwardly facing convex crushing surface and the downwardly facing concave crushing surface defines a crushing gap having a scalar dimension G.
Material to be crushed is fed downwardly into the annular crushing chamber and is crushed by gyration of the convex crushing head by the eccentric shaft. The maximum particle size, as well as the particle size distribution, of the output from the gyrasphere crusher is dependent in part upon the magnitude of the crushing gap. Particle size adjustment and/or compensation for wear on the opposed crushing surfaces of the conical convex crushing head and the conical concave crushing bowl is thus possible by mounting the conical concave crushing bowl on the main frame for vertical movement with respect to the main frame, and therefore with respect to the conical convex crushing head. The crushing gap is widened by raising the conical concave crushing bowl or narrowed by lowering the conical concave crushing bowl. To permit such adjustment, the conical concave crushing bowl includes a crushing bowl frame that is threadedly connected to an upper portion of the main frame. The conical concave crushing bowl is raised or lowered by rotating the entire conical concave crushing bowl in the appropriate direction relative to the main frame.
When satisfactorily adjusted, the conical concave crushing bowl must be locked in place or substantially prevented from rotating relative to the main frame in response to the tangential forces imposed upon it by the gyrating crushing head. This locking is typically performed via a conventional locknut or jam nut. A substantial clamping force is normally exerted between the conical concave crushing bowl and the locknut to urge them axially towards one another. For adjusting the conical concave crushing bowl, this clamping force is released.
A previously recognized problem has been that a significant amount of force is needed to rotate the conical concave crushing bowl. What is needed therefore is an apparatus that provides enough force to rotate the conical concave crushing bowl. Such apparatus must be strong, durable, reliable under harsh operating conditions, and economical. Heretofore these requirements have not been fully met without incurring various disadvantages.
One previously recognized solution to the problem of adjusting the crushing gap G was to rotate the conical concave crushing bowl by means of a chain attached between a lug that is connected to the conical concave crushing bowl and a rigid puller post connected to the stationary main frame. This solution is disclosed at page 21 of Operation and Maintenance Telsmith Model D Style 36 VFC and 48 VFC Crushers. According to this solution, the chain is shortened with a chain puller, thereby rotating the conical concave crushing bowl. A disadvantage of this previously recognized solution is that tools must be used to reverse the orientation of the entire rigid puller post when the direction of rotation is to be reversed so as to avoid bending the rigid post puller when the chain is shortened. Further, this previously recognized solution also has the disadvantage that the threads of the stud to which the rigid puller post is attached may become damaged due to the large amount of force that is applied to the rigid puller post by the chain puller. Such damage is cumulative and particularly likely to occur if the rigid post puller is cross-threaded onto the stud due to ordinary wear and tear, or human error. Significantly, such damage may prevent reorientation of the rigid puller post and/or impede removal of the associated stud.
The below-referenced U.S. patents disclose embodiments that were at least in-part satisfactory for the purposes for which they were intended but which had certain disadvantages.
U.S. Pat. No. 3,397,846 discloses a hydraulic piston for applying force to a chain so as to thereby rotate a concave crushing bowl. The free end of the chain is disclosed to be engaged with a chain wheel provided with a ratchet and a spring pressed pawl.
U.S. Pat. No. 3,396,915 discloses a pair of hydraulic pistons for applying force to a concave crushing bowl so as to thereby rotate the bowl. The crushing bowl can be rotated in either direction.
U.S. Pat. No. 3,350,019 discloses a continuous chain for continuously rotating a concave crushing bowl. The bowl can be rotated in either direction without manual adjustment.
U.S. Pat. No. 3,201,053 discloses a hydraulic piston for applying force to a chain so as to thereby rotate a concave crushing bowl. The free end of the chain is hooked around the bracket to which the hydraulic piston is attached.
In embodiments disclosed in the above-referenced prior patents, apparatus for rotating a conical concave crushing bowl is disclosed as being either electrical or hydraulic. As indicated above, such apparatus has the disadvantage that it is not entirely reliable under harsh operating conditions. Further, as indicated above, such apparatus also has the disadvantage that it is relatively complex for the task and is not economical.